ULTRASONIC ERADICATION OF SEA LICE ON FARMED FISH

Abstract

A method, and device for removing sea lice from salmon with use of a salmon herding passage tube, with ultrasound transducers on the periphery thereof, in a number sufficient to provide ultrasound treatment of the salmon being herded therethrough at a normal herding rate and at a sufficiently high enough frequency to kill the sea lice. Salmon are herded therethrough, with the application of ultrasound from the ultrasonic. The method and device also include removal of the lice from a salmon cage or enclosure with feeding fish into an enclosure having ultrasound transducers situated on the inner periphery thereof and providing an attraction such as a white light which attracts noxious parasitic aquatic organisms and applying ultrasound from the electronic transducers within the enclosure.

Claims

1. A method for treatment of fish to remove parasitic, noxious aquatic organisms having gas pockets therein, from the fish, comprising the steps of: 1) providing a fish herding passage element with ultrasound transducers on a periphery thereof and in a number sufficient to provide ultrasound treatment of the fish being herded therethrough at a normal herding rate and at a sufficiently high enough frequency to kill the parasitic, noxious aquatic organisms; and 2) herding fish therethrough, with the application of ultrasound from the ultrasonic transducers at the sufficiently high frequency and at a herding rate sufficient to enable each fish to be exposed to the ultrasound, for the acoustic cavitation and killing of parasitic, noxious aquatic organisms thereon.

2. The method of claim 1 wherein ultrasound from the ultrasound transducers is emitted with a frequency at or above 20000 Hz and below a frequency harmful to the fish.

3. The method of claim 1, wherein the fish herding passage element is a pipe section of at least 20 feet in length and a diameter of at least one foot.

4. The method of claim 3, wherein spaced areas of the pipe section are circumferentially provided with a plurality of ultrasound transducers directed toward an interior of the pipe through which the fish are herded.

5. The method of claim 4, wherein the plurality of ultrasound transducers is four and wherein the pipe section has at least ten spaced areas circumferentially each provided with the four ultrasound transducers.

6. The method of claim 1, wherein the fish herding passage element is interiorally lined with stainless steel and exteriorally covered with a soft sound absorbing composite material.

7. The method of claim 1, wherein the parasitic, noxious aquatic organism is sea lice and the fish is salmon.

8. A method for treatment of an enclosure containing fish to remove parasitic, noxious aquatic organisms having gas pockets therein, from affecting the fish, comprising the steps of: i) feeding fish into the enclosure having ultrasound transducers situated on the inner periphery thereof; ii) providing an attractant which attracts the parasitic, noxious aquatic organisms thereto within the enclosure; and iii) applying ultrasound from the ultrasound transducers within the enclosure at a sufficiently high enough frequency and application time for the acoustic cavitation and killing of parasitic noxious aquatic organisms within the enclosure.

9. The method of claim 8, wherein the frequency is at or above 20,000 Hz and below a frequency harmful to the fish.

10. The method of claim 8, wherein the attractant is a white light.

11. The method of claim 8, wherein the parasitic, noxious aquatic organism is sea lice and the fish is salmon.

12. A fish herding passage element configured for use in the method of claim 1, comprising a tube passage having a plurality of cross sectional areas each with multiple ultrasound transducers positioned around an exterior circumferential section thereon and the ultrasound transducers being directed to the interior of the tube passage.

13. The fish herding passage element wherein the interior of the tube is lined with stainless steel and the exterior of the tube is covered with a soft sound absorbing composite material.

14. A enclosure for fish configured for use in the method of claim 8 comprising a plurality of peripherally placed ultrasound transducers and an attractant generator configured to provide an attractant to attract noxious, parasitic aquatic organisms between the ultrasound transducers.

Description

SHORT DESCRIPTION OF THE DRAWINGS

[0018] FIG. 1 is a depiction of a prior art ultrasound device as used for the disinfection and purification of ship ballast waters.

[0019] FIG. 2 is a depiction of a fish herding pipe with multiple outlets each having a centrally located ultrasound transducer.

[0020] FIGS. 3a and 3b are isometric and end views respectively of a single herding pipe with peripherally placed ultrasound transducers; and

[0021] FIG. 4 is upper view of a series of ten fish cages with inner peripherally situated ultrasound transducers.

DETAILED DESCRIPTION OF THE INVENTION AND DRAWINGS

[0022] Mechanisms of bioeffects of ultrasound include thermal and mechanical effects. When ultrasound waves are absorbed by plants, energy associated with ultrasound waves is converted into heat, known as thermal effect. An ultrasound wave as it passes through an aqueous medium, may cause bubble activities known as acoustic cavitation. Cavitation causes a wide variety of changes in plant cells, ranging from microstreaming of a cell's internal structure, to a mass disruption of the cell wall. Acoustic cavitation, the dominant mechanism in many applications, is especially evident on aquatic organisms due to the presence of gas inside of aquatic organisms. The gas pockets typically are microscopic in size. Those gas pockets have a high potential to absorb acoustic energy very effectively.

[0023] Ultrasound is particularly effective in eliminating microscopic parasitic aquatic organisms, including copepods. Mortality rates are greater than 99.999%. Under exposure of ultrasound, the ultrasonic energy causes bubbling effects or acoustic cavitation inside of copepods. Cavitation damages the internal structure of copepods and causes death of the organisms. Ultrasound also is very effective in disinfection or killing microorganisms. The continuous flow ultrasonic treatments on microbes in milk and apple cider found up to 99.999% reduction in Listeria monocytogenes and 99.999% reduction in total aerobic bacteria in raw milk, and 99.999% reduction in E. coli. Ultrasound application to insects generates various adverse and deteriorating changes in morphological, biochemical and functional conditions.

[0024] Ultrasounds can effectively eliminate copepods. Low frequency ultrasound, has, on the other hand, very limited effects on fish. Ultrasound can effectively kill copepods in less than 10 seconds. However, the same sound frequency that can effectively control copepods were found to have no impact on fish physiology or behavior.

[0025] Accordingly, only a few seconds of ultrasound exposure can successfully kill copepods without hurting fish and ultrasonic devices may be used for sea lice treatment and prevention in salmon farms particularly with eliminating free-swimming sea lice in farm water for sea lice outbreak prevention and for treating sea lice attached on fish. It is believed that the reflective nature of parts of fish bodies such as scales may serve to deflect ultrasound waves from having primary or residual effects on the fish, as opposed to the noxious aquatic organisms which are quickly and fatally affected by the ultrasound waves.

[0026] In order to facilitate and efficiently concentrate the effects of the ultrasound waves while protecting exterior environments, in one embodiment of the invention, the fish herding pipes and fish containing enclosures are interiorally lined with stainless steel and exteriorally covered with a soft, sound-deadening composite material. As a result, the generated ultrasound waves are continuously directed toward the fish and noxious aquatic organisms while the exterior environment is shielded from the ultrasound waves.

[0027] Currently, chemical treatment is applied after a sea lice outbreak. In accordance with embodiments of the invention, a first ultrasonic device, in embodiments herein, can terminate free-swimming sea lice to prevent an outbreak, and a second device can be used to treat sea lice on fish during and after an outbreak. Ultrasound technology is cost-effective, environmentally-sound, exhibits low fish mortality, and comprises a low maintenance alternative for sea lice treatment and prevention.

[0028] With reference to the drawings, in FIG. 1, a prior art mechanism for ultrasonic treatment of ballast water is shown with the ballast water or influent containing aquatic invaders or organisms from local sites in the ballast tank 10. The influent 1 is fed through a valve 11 through filter system 12 by means of water pump 20. The influent is then fed through controlled valve 13 and an ultrasonic treatment pipe 14 with operation of controller and power amplifier 15 and 16. The influent 1 is finally pumped into tank 17 as fully treated influent 1. The system is however not amenable for the flow of anything except water and microorganisms for providing resultant treated influent entirely clear of any organisms.

[0029] As shown in FIG. 2, a multiple section fish herding pipe section 100 is shown with peripherally positioned ultrasonic transducer pipes 101-104 with each containing an ultrasonic transducer 110. Lice carrying fish are herded through inlet 105, and treated at section 106 and exit outlet 107 for harvesting or movement into cages from outlet 107.

[0030] FIG. 3a schematically depicts an elongated large pipe 120 comprised of ten pipe sections 100 of FIG. 2 with each having separate transducer containing pipes 101-104 (power mechanisms for the respective transducers are not shown). FIG. 3b depicts an end view of the pipe 120 with aligned transducer containing pipes 101-104.

[0031] FIG. 4 is an aerial top view of a system collection 130 of a series of ten fish cages 140-149 with each having four internal ultrasound transducers 151-154. As shown, the total system is about 100 meters by 250 meters in width and length with each cage being about 50 by 50 meters. The interior circles 155 indicate the position at which an attractant such as a white light is beamed for attraction of loose noxious parasitic organic organisms to gather at a focal point between the respective transducers 151-154 for maximum killing effectiveness of the organisms.

[0032] It is understood that the above description and drawings are exemplary of the invention and that changes in the method and structure used with the ultrasonic transducers is possible without departing from the scope of the invention as defined in the following claims.